Data from: Ants on Clerodendrum infortunatum: disentangling effects of larceny and herbivory

Nectar larcenists extract nectar from flowers without pollinating them. A
reasonable expectation is that any form of nectar larceny should have a
detrimental effect on the plant’s reproductive success. However, studies
reveal an entire range of effects, from highly negative to highly
positive. This variation in effect may be partly explained by additional,
unmeasured, effects of nectar larcenists on plants. In a study system
where two ant species Tapinoma melanocephalum (Fabr.) and Trichomyrmex
destructor (Jerd.) act as nectar larcenists, we examined the effect of
larceny on the female reproductive success of Clerodendrum infortunatum
Gaertn. in rain forest fragments of the Western Ghats, India. This was
done through a combination of field observations and a series of field
experiments looking at the effects of excluding ants from inflorescences.
We found that T. destructor reduces fruit set considerably. Rather than
this being a consequence of nectar larceny, however, our experiments show
that the negative effect arises instead from the herbivorous behaviour of
the ant. At a population level, both ant species prefer edges over
interiors of forest patches, spatially concentrating the interaction zone
to forest edges. Simultaneously considering multiple ecological
interactions and disentangling their relative contributions might explain
the large variation across species in the observed effect of larceny. The
overall population effect of nectar larceny and herbivory is likely to
depend on the spatial structuring of plants and ants.